In nuclear medicine procedures, a bolus of radioactive liquid is injected into a blood vessel. The progress or dispersal of the bolus is monitored by a radioactive sensing system with which one may then obtain an indication of heart or other vascular diseases.
Prior art techniques in the injection of a radioactive bolus typically involve apparatus as depicted in FIGS. 1 and 2. Thus, a syringe 10 is inserted into a vial 12 containing a radioactive liquid 14.
The amount or size of the bolus taken in by syringe 10 would depend upon the radioactive dosage needed for the particular procedure, the person in whose blood system the bolus is to be injected and such other factors as are generally well understood in the nuclear medicine field.
The filled or partially filled syringe 10 is then placed on an input port 16 of a three-way conventional valve 18 controlled by a manual control cock 20 and having another input port 22. An output port 24 is connected to a long flexible tube 26 which, at one end 28, is connected to a hypodermic needle 30 placed in a catheter inserted in a blood vessel 32. A flushing syringe 34 containing a supply of sterile saline solution is applied to input port 22.
To avoid the insertion of a significant amount of harmful air into blood vessel 32, the flushing syringe 34 is first actuated to fill flexible tube 26 with saline solution while the needle 30 is out of vessel 32. Thereupon, the valve 20 is actuated so that the radioactive bolus 36 in syringe 10 can be moved into tube 26 such as at 38 by emptying the syringe 10.
The valve 20 is then changed so that saline solution from flushing syringe 34 can be inserted into tube 26 behind bolus 36 and thus advance the bolus 36 for injection into blood vessel 32.
Since the bolus 36 is a radioactive substance, it is normal practice to protect the technician, physician or nurse who is administering the bolus against radiation with a lead shield 40 in the form of a cylinder and sized to fit over syringe 10. The shield, although affective when installed, is not able to protect the user throughout the procedure. Thus, after initial take-up of the bolus 36 in syringe 10 when the bolus is transferred to the flexible tube 26 at 38 the person applying the procedure is exposed to radiation. Though the radiation level for any one bolus is low, the administering of many tests can result in the accumulation of a radiation dosage which is extremely hazardous over an extended time period.